1. Field of the Invention
The present invention relates to a loop hanger for a seat belt which slidably supports a seat belt webbing (webbing belt) so as to turn over the seat belt at its intermediate portion, the seat belt being provided such that it can be pulled out in an ordinary situation of a vehicle and it can be prevented from being pulled out in an emergency situation of the vehicle, for example, like a three-point seat belt system for an automobile, and a method for manufacturing the same.
2. Description of the Related Art
In recent years, in order to protect an occupant of an automobile at a time of a vehicle collision, a three-point type seat belt which holds the beast of an occupant in a manner extending from the waist of the occupant to his/her one shoulder has been proposed in addition to a two-point type seat belt which holds the waist of the occupant.
Prior to specific explanations to the Related Art, a general and basic structure of a three-point seat belt 70 capable of using a loop hanger according to the invention by referring to FIG. 3 which is a perspective view of an interior of an automobile 1, is explained. Incidentally, the tree-point seat belt 70 is provided at each of front seats and rear seats. However, an example of a seat belt system provided at a driver""s seat 2 will be explained below for simplification of explanation.
The tree-point type seat belt 70 is extended so as to reach three points of a first anchor 71 provided at a lower portion of a center pillar 3, a second anchor 72 provided on a portion of a floor positioned between the driver""s seat 2 and a front passenger""s seat 4, and a third anchor 73 provided at an upper portion of the center pillar 3. The three-point type seat belt 70 comprises a webbing belt or a seat belt webbing S, one end thereof being mounted to the first anchor 71 and the other end being taken up or retracted in a retractor (not shown), and a fixing belt 75, one end thereof being mounted to the second anchor 72 and the other end having a buckle device 77. Also, a tongue portion or plate 76 which is locked to the buckle device 77 is provided at an intermediate portion of the webbing belt S.
FIG. 1 is a perspective view of a conventional loop hanger for a seat belt 100 mounted to the third anchor 73. The loop hanger for a seat belt 100 is provided with a base member 80 which is made of a steel plate (metal) and which has a bolt passing-through hole 81 for mounting the loop hanger 100 to the third anchor 73 through a bolt and a base slot 82 (refer to FIG. 2) through which the webbing belt S is moved in the loop hanger 100 in a sliding manner, and the periphery of the base slot 82 of the base member 80 is entirely covered with a cover member 90 made of synthetic resin, which is insert-molded.
This cover member 90 covers an edge portion 82a of the base slot 82 to form a slot 91 through which the webbing belt S is slidably moved along the edge portion 82a of the base slot 82. That is, the webbing belt S is turned back at a lower edge face portion of the slot 91 and it can be pulled out from/taken up in the retractor.
However, since the slot 91 is formed by covering the edge portion 82a of the base slot 82 with the cover member 90 which is made of synthetic resin and which is insert-molded, the slidability of the webbing belt S is apt to lower according to reduction of anti-gum up property.
The present invention has been made to solve the above problem and an object thereof is to provide a loop hanger for a seat belt which can be maintained with the slidability of the webbing belt without influenced by reduction of anti-gum up property and which can reduce fraction defective or reduce a occurrence ratio of inferior goods, and a method for manufacturing the same.
To achieve the object, according to a first aspect of the present invention, there is provided a loop hanger for a seat belt (10) which slidably hangs a seat belt webbing (S), comprising a base member (20) made of a metal plate and having a slot (21) through which the seat belt webbing (S) is moved, wherein the slot (21) is constituted with a long side portion (21a) extending in a generally horizontal direction and a pair of left and right short side portions (21b) communicating with left and right end portions of the long side portion (21a) and extending downwardly, a portion of the base member (20) surrounded by the long side portion (21a) and the pair of short side portions (21b) is curved smoothly from a side of the long side portion (21a) in a generally C-shaped sectional configuration, and a curved face (21f) formed by curving the portion of the base member (20) serves as a portion (20a) through which the seat belt webbing (S) is turned back.
Therefore, according to the first aspect of the present invention structured in the above manner, since the base member (20) is structured such that at least the portion (20a) through which the seat belt webbing (S) is turned back is formed integrally with the base member (20) so as to curve smoothly in a generally C-shaped sectional configuration, face pressure acting upon the seat belt webbing (S) can be reduced, thereby improving durability of the seat belt webbing (S), and the thickness of the base member (20) can be reduced, thereby achieving weight-reduction and cost-reduction.
Also, since the base member (20) is made of a metal plate and the portion (20a) through which the seat belt webbing (S) is turned back is formed in a curved face so as to curve smoothly in a generally C-shaped sectional configuration, the loop hanger for a seat belt can be maintained with the slidability of the webbing belt without influenced by reduction of anti-gum up property.
According to a second aspect of the invention, there is provided a loop hanger for a seat belt (10) which slidably hangs a seat belt webbing (S), comprising a base member (20) made of a metal plate and having a slot (21) through which the seat belt webbing (S) is moved; and a cover member (30) which covers a portion of the base member (20) other than at least a portion (20a) of the base member (20) through which the seat belt webbing (S) is turned back, wherein the slot (21) of the base member (20) is constituted with a long side portion (21a) extending in a generally horizontal direction and a pair of left and right short side portions (21b) communicating with left and right end portions of the long side portion (21a) and extending downwardly, a portion of the base member (20) surrounded by the long side portion (21a) and the pair of short side portions (21b) is curved smoothly from a side of the long side portion (21a) in a generally C-shaped sectional configuration, and a curved face (21f) formed by curving the portion of the base member (20) serves as a portion (20a) through which the seat belt webbing (S) is turned back, and wherein the cover member (20) is provided so as to cover a portion of the base member (20) other than at least the portion (20a) through which the seat belt webbing (S) is turned back and which is formed in a generally C-shaped sectional configuration.
In addition to the above operation and effect, since the cover member (30) is formed so as to cover the portion of the base member (20) other than the portion (20a) through which the seat belt webbing (S) is turned back, the seat belt webbing (S) directly slides on the metal plate-made portion (20a) with the generally C-shaped sectional configuration through which the seat belt webbing (S) is turned back, so that the loop hanger for a seat belt can be maintained with the slidability of the webbing belt without influenced by reduction of anti-gum up property.
According to a third aspect of the invention, there is provided a loop hanger for a seat belt according to the first or second aspect, wherein the center of curvature of the curved face (21f) with the generally C-shaped sectional configuration constituting the portion (20a) through which the seat belt webbing (S) is turned back is positioned on a side of the center of the thickness of the base member (20).
Therefore, according to the third aspect of the invention, since the center of curvature of the curved face (21f) with the generally C-shaped sectional configuration constituting the portion (20a) through which the seat belt webbing (S) is turned back is positioned on the side of the center of the thickness of the base member (20).
According to a fourth aspect of the invention, there is provided a loop hanger for a seat belt according to any one of the first to third aspects, wherein, regarding the slot (21) of the basis member (20), a coarse surface portion (20c) is formed on the portion (20a) through which the seat belt webbing (S) is turned back and which is formed in the generally C-shaped sectional configuration.
Since the coarse surface portion (20c) is formed on the metal plate-made portion (20a) with the generally C-shaped sectional configuration through which the seat belt webbing (S) is turned back, the seat belt webbing (S) slides on the coarse surface portion (20c) directly.
According to a fifth aspect of the invention, there is provided a loop hanger for a seat belt according to any one of the first to fourth aspects, wherein reinforcement ribs (R) are provided on both left and right sides of the slot (21) of the base member (20).
In the above construction according to the fifth aspect of the invention, since the reinforcement ribs (R) are provided on both the left and right sides of the slot (21) on the base member (20), both portions of the base member (20) which are positioned on the both sides of the slot (21) can be improved in strength. Accordingly, even when the seat belt webbing (S) is moved to one of the both sides and pressure of the webbing (S) is concentrated on the one, safety of the seat belt webbing (S) can be improved.
According to a sixth aspect of the invention, there is provided a loop hanger for a seat belt according to the fifth aspect, wherein the reinforcement ribs (R) are formed on the both left and right sides of the slot (21) of the base member (20) along an opening edge, and a sectional configuration of each reinforcement rib has a generally semi-circular sectional configuration projecting on one side surface of the base member (20).
According to the sixth aspect of the invention, since the reinforcement ribs (R) are provided on the both edge sides of the slot (21) along the opening edge and each rib (R) projects on one side surface of the base member (20) in a semi-circular or semi-spherical sectional configuration, the seat belt webbing (S) can be rounded along a direction in which the seat belt webbing (S) is turned back so that the seat belt webbing (S) can be prevented from being injured.
According to a seventh aspect of the invention, there is provided a loop hanger for a seat belt according to the fifth aspect, wherein the reinforcement ribs (R) are formed on the both left and right sides of the slot (21) of the base member (20) along an opening edge, and a sectional configuration of each reinforcement rib has a generally circular sectional configuration projecting on both side surfaces of the base member (20).
Since each reinforcement rib (R) is provided on both side surfaces of the base member (20) so as to project in a circular or spherical sectional configuration, the seat belt webbing (S) can be rounded along a direction in which the seat belt webbing (S) is turned back so that the seat belt webbing (S) can be prevented from being injured and the strength thereof can further be improved.
According to an eighth aspect of the invention, there is provided a method for manufacturing a loop hanger for a seat belt (10) which slidably hangs a seat belt webbing (S), wherein, after a slot (21) which comprises a long side portion (21a) extending in a generally horizontal direction and a pair of left and right short side portions (21b) communicating with left and right end portions of the long side portion (21a) and extending downwardly, and through which the seat belt webbing (S) is moved is pierced in a material member made of a metal plate to form a base member (20) made of the metal plate, a portion of the base member (20) which is surrounded by the long side portion (21a) and the pair of left and right short side portions (21b) is curved smoothly from the long side portion (21a) side in a generally C-shaped sectional configuration to form a curved face (21f) and a portion (20a) through which the seat belt webbing (S) is turned back is formed by the curved face (21f); and the center of curvature of the curved face 21f) constituting the portion (20a) through which the seat belt webbing (s) is turned back is moved to a side of the center of the thickness of the base member (20).
According to a ninth aspect of the invention, there is provided a method for manufacturing a loop hanger for a seat belt (10) which slidably hangs a seat belt webbing (S), wherein, after a slot (21) which comprises a long side portion (21a) extending in a generally horizontal direction and a pair of left and right short side portions (21b) communicating with left and right end portions of the long side portion (21a) and extending downwardly, and through which the seat belt webbing (S) is moved is pierced in a material member made of a metal plate to form a base member (20) made of the metal plate, a portion of the base member (20) which is surrounded by the long side portion (21a) and the pair of left and right short side portions (21b) is curved smoothly from the long side portion (21a) in a generally C-shaped sectional configuration to form a curved face (21f) and a portion (20a) through which the seat belt webbing (S) is turned back is formed by the curved face (21f); the center of curvature of the curved face (21f) constituting the portion (20a) through which the seat belt webbing (S) is turned back is moved to a side of the center of the thickness of the base member (20) to form the base member (20) which is provided with the portion (20a) through which the seat belt webbing (S) is turned back; and a cover member (30) is provided so as to cover a portion of the base member (20) other than at least the portion (20a) through which the seat belt webbing (S) is turned back.
According to a tenth aspect of the invention, there is provided a method for manufacturing a loop hanger for a seat belt (10) which slidably hangs a seat belt webbing (S), wherein, after a slot (21) which comprises a long side portion (21a) extending in a generally horizontal direction and a pair of left and right short side portions (21b) communicating with left and right end portions of the long side portion (21a) and extending downwardly, and through which the seat belt webbing (S) is moved is pierced in a material member made of a metal plate to form a base member (20) made of the metal plate, the center of curvature of a curved face (21f) to be formed in the next step is moved to a side of the center of the thickness of the base member (20) in advance; and a portion of the base member (20) which is surrounded by the long side portion (21a) and the pair of left and right short side portions (21b) is curved smoothly from the long side portion (21a) in a generally C-shaped sectional configuration to form a curved face (21f) and a portion (20a) through which the seat belt webbing (S) is turned back is formed by the curved face (21f).
According to an eleventh aspect of the invention, there is provided a method for manufacturing a loop hanger for a seat belt (10) which slidably hangs a seat belt webbing (S), wherein, after a slot (21) comprising a long side portion (21a) extending in a generally horizontal direction and a pair of left and right short side portions (21b) communicating with left and right end portions of the long side portion (21a) and extending downwardly is formed in material made of a metal plate to form a base member (20) made of the metal plate, the center of curvature of a curved face (21f) to be formed in the next step is moved to a side of the center of the thickness of the base member (20) in advance; a portion of the base member (20) which is surrounded by the long side portion (21a) and the pair of left and right short side portions (21b) is curved smoothly from the long side portion (21a) in a generally C-shaped sectional configuration to form a curved face (21f) and a portion (20a) through which the seat belt webbing (S) is turned back is formed by the curved face (21f); and a cover member (30) is provided so as to cover a portion of the base member (20) other than at least the portion (20a) through which the seat belt webbing (S) is turned back.
According to each of the eighth to eleventh aspects of the invention, since the portion (20a) through which the seat belt webbing (S) is turned back is formed in a curved face having a large radius of curvature such that the seat belt webbing (S) is smoothly curved, the face pressure acting upon the seat belt webbing (S) can be made small, so that the durability of the seat belt webbing (S) can be improved and the thickness of the base member (20) can be reduced, thereby decreasing weight and manufacturing cost.
Also, since the base member (20) is made of a metal plate and the portion (20a) through which the seat belt webbing (S) is turned back is formed in a curved face so as to curve smoothly in the generally C-shaped sectional configuration, the loop hanger for a seat belt can be maintained with the slidability of the webbing belt without influenced by reduction of anti-gum up property.